Ive recently started to restore some vr troopers episodes, but i am having trouble with a sound i get and i dont know if it can be fixed or if i have done something wrong.

Ive been using Adobe soundbooth CS5, on the episode before i put any effects to fix the problems i get a hiss, along with low sound (no loud screeching noise).

When i put on the noise effect to fix the hiss, i tried 100 High and 30db, i tried different settings and its still the same. then i put the effect to equilize the volume levels. Then once ive done that filter i hear the Loud screeching noise very clearly.

What have i done wrong and how can i fix this? appreciate any help, the sooner the better so i can move on. thanks..